#include "FEDataStructures.h"

#include <mpi.h>
#include <iostream>

Grid::Grid()
{}

void Grid::Initialize(const unsigned int numPoints[3], const double spacing[3] )
{
  if(numPoints[0] == 0 || numPoints[1] == 0 || numPoints[2] == 0)
    {
    std::cerr << "Must have a non-zero amount of points in each direction.\n";
    }
  // in parallel, we do a simple partitioning in the x-direction.
  int mpiSize = 1;
  int mpiRank = 0;
  MPI_Comm_rank(MPI_COMM_WORLD, &mpiRank);
  MPI_Comm_size(MPI_COMM_WORLD, &mpiSize);

  unsigned int startXPoint = mpiRank*numPoints[0]/mpiSize;
  unsigned int endXPoint = (mpiRank+1)*numPoints[0]/mpiSize;
  if(mpiSize != mpiRank+1)
    {
    endXPoint++;
    }

  // create the points -- slowest in the x and fastest in the z directions
  // all of the x coordinates are stored first, then y coordinates and
  // finally z coordinates (e.g. x[0], x[1], ..., x[n-1], y[0], y[1], ...,
  // y[n-1], z[0], z[1], ..., z[n-1]) which is OPPOSITE of VTK's ordering.
  size_t numTotalPoints = (endXPoint-startXPoint)*numPoints[1]*numPoints[2];
  this->Points.resize(3*numTotalPoints);
  size_t counter = 0;
  for(unsigned int i=startXPoint;i<endXPoint;i++)
    {
    for(unsigned int j=0;j<numPoints[1];j++)
      {
      for(unsigned int k=0;k<numPoints[2];k++)
        {
        this->Points[counter] = i*spacing[0];
        this->Points[numTotalPoints+counter] = j*spacing[1];
        this->Points[2*numTotalPoints+counter] = k*spacing[2];
        counter++;
        }
      }
    }

  // create the hex cells
  unsigned int cellPoints[8];
  unsigned int numXPoints = endXPoint - startXPoint;
  for(unsigned int i=0;i<numXPoints-1;i++)
    {
    for(unsigned int j=0;j<numPoints[1]-1;j++)
      {
      for(unsigned int k=0;k<numPoints[2]-1;k++)
        {
        cellPoints[0] = i*numPoints[1]*numPoints[2] +
          j*numPoints[2] + k;
        cellPoints[1] = (i+1)*numPoints[1]*numPoints[2] +
          j*numPoints[2] + k;
        cellPoints[2] = (i+1)*numPoints[1]*numPoints[2] +
          (j+1)*numPoints[2] + k;
        cellPoints[3] = i*numPoints[1]*numPoints[2] +
          (j+1)*numPoints[2] + k;
        cellPoints[4] = i*numPoints[1]*numPoints[2] +
          j*numPoints[2] + k+1;
        cellPoints[5] = (i+1)*numPoints[1]*numPoints[2] +
          j*numPoints[2] + k+1;
        cellPoints[6] = (i+1)*numPoints[1]*numPoints[2] +
          (j+1)*numPoints[2] + k+1;
        cellPoints[7] = i*numPoints[1]*numPoints[2] +
          (j+1)*numPoints[2] + k+1;
        std::copy(cellPoints, cellPoints+8, std::back_inserter(this->Cells));
        }
      }
    }
}

size_t Grid::GetNumberOfPoints()
{
  return this->Points.size()/3;
}

size_t Grid::GetNumberOfCells()
{
  return this->Cells.size()/8;
}

double* Grid::GetPointsArray()
{
  if(this->Points.empty())
    {
    return NULL;
    }
  return &(this->Points[0]);
}

bool Grid::GetPoint(size_t pointId, double coord[3])
{
  if(pointId >= this->Points.size()/3)
    {
    return false;
    }
  coord[0] = this->Points[pointId];
  coord[1] = this->Points[pointId+this->GetNumberOfPoints()];
  coord[2] = this->Points[pointId+2*this->GetNumberOfPoints()];
  return true;
}

unsigned int* Grid::GetCellPoints(size_t cellId)
{
  if(cellId >= this->Cells.size())
    {
    return NULL;
    }
  return &(this->Cells[cellId*8]);
}

Attributes::Attributes()
{
  this->GridPtr = NULL;
}

void Attributes::Initialize(Grid* grid)
{
  this->GridPtr = grid;
}

void Attributes::UpdateFields(double time)
{
  size_t numPoints = this->GridPtr->GetNumberOfPoints();
  this->Velocity.resize(numPoints*3);
  double coord[3] = {0, 0, 0};
  for(size_t pt=0;pt<numPoints;pt++)
    {
    this->GridPtr->GetPoint(pt, coord);
    this->Velocity[pt] = coord[1]*time;
    }
  std::fill(this->Velocity.begin()+numPoints, this->Velocity.end(), 0.);
  size_t numCells = this->GridPtr->GetNumberOfCells();
  this->Pressure.resize(numCells);
  std::fill(this->Pressure.begin(), this->Pressure.end(), 1.);
}

double* Attributes::GetVelocityArray()
{
  if(this->Velocity.empty())
    {
    return NULL;
    }
  return &this->Velocity[0];
}

float* Attributes::GetPressureArray()
{
  if(this->Pressure.empty())
    {
    return NULL;
    }
  return &this->Pressure[0];
}